The invention relates to fuel management of internal combustion engines. More particularly, the invention relates to an apparatus to be used in association with a fuel injection system for internal combustion engines. The fuel injection system with which this apparatus is associated is one that employs electromagnetic fuel injection valves that are actuated by electrical control pulses which are generated on the basis of the sensed magnitude of engine variables, for example the air flow rate and engine speed. In known fuel injection systems of this type, the fuel control pulses are entirely suppressed and fuel supply is entirely interrupted whenever the throttle valve of the engine is completely closed while the engine is maintaining a speed above a certain minimum. This combination of conditions indicates so-called overrunning or downhill operation (negative engine torque). The known mechanisms for terminating fuel delivery by suppressing the control pulses include sensors for detecting the position of the throttle valve as well as further sensors for detecting engine speed. In addition, the known pulse suppressor systems require engine temperature information so as to set the points at which the control pulses are suppressed and readmitted. These various sensors increase the cost of the known apparatus and increase its space requirement as well as diminishing its reliability.